Mailing List Archive

Jeremy Fang wrote:
> According to the manual, it says: "The first step in creating a new
> domain is to prepare a root
> filesystem for it to boot off. .... A simple way to do this is simply to
> boot from your standard OS install CD and install the distribution into
> another partition on your hard drive."
>
> My current df output is like the following:
>
> Filesystem 1K-blocks Used Available Use% Mounted on
> /dev/sda3 33198856 2564736 28947700 9% /
> /dev/sda1 101089 24895 70975 26% /boot
> none 65536 0 65536 0% /dev/shm
>
> If I put RedHat 8.0 in CD and boot from there, which partition I am
> going to choose from ?
>
> Really appreciate if someone could shed some light on this setup.

It looks like you used up all your hard drive space in one
partition(unless your harddrive is bigger than 34 gig).

Either install parted and resize your / partition, or reinstall and set
up smaller partitions when you get to the fdisk stage.

It looks like your install took 2.5GB. Carving off 4-5 GB ought to cover
that installation fine. (You can go less than that, but you might need
to stretch things out over multiple partitions in the future.) It's up
to you...

Once you're done with either of those steps, reboot off the CD again,
and do a fresh install to a different place than your original
install(say /dev/sda4 or 5 or 6). When you get to the finalize/set up
your kernel/configure bootdisk phase, be careful you don't overwrite
your base install.

Does RedHat use GRUB? I think it's a requirement for booting Xen, so be
prepared to set that up as well.

For starters, download the 2.0-stable-install tgz and try booting that.
After you get a working system, you can start fiddling with building
your own XenLinux kernels.

--
Andrew Thompson
http://aktzero.com/

Jeremy Fang wrote:
> Hi Andrew:
>
> Thanks for you quick reply. I have another problem after I follow you steps:
>
> 1) I repartition the disks to be
> /dev/sda1 / 4GB
> /dev/sda2 /rh80 10 GB
> /dev/sda5 /rh72 20 GB
> 1 GB for swap
>
> 2) I installed RedHat Enterprise Linux version 3 on /dev/sda1
>
> 3) I installed RedHat 8.0 on /dev/sda2 by specifying / in the partition
> window
>
> After system reboot, it will always boot onto RedHat 80.
>
> How I can boot to /dev/sda1 which is my RedHat Enterprise Linux version
> 3 which will be latered on install the xen ?
>
> I played around fdisk /dev/sda and it seem Boot flag (*) points to /dev/sda1
>
> Device Boot Boot Start End
>
> ./dev/sda1 * 1 510
> /dev/sda2 511 1785
>
> Why I can not boot to /dev/sda1 ?
>
> The other option I have is to install RedHat 8.0 first and then install
> RedHat Enterprise Linux version 3 last so that I can boot off from it
> to continue the xen installation.
>
> Any suggestions ?

I don't use RedHat, so my steps will be sort of vague. You should keep
your replies on list, where other more versed people can respond to them.

Reboot your machine. (You may have to do this several times to engross
yourself in the process.)

Watch it carefully, for signs of a boot loader. I've only seen GRUB and
LILO as bootloaders, but RedHat could use something different. The
bootloader starts after your video card and system BIOS messages. It
looks like you're running SCSI, so you'll probably see a message saying
"looking for devices", after which it'll list your hard drive(s) and
possibly CDROM(s).

When you see something that looks like a bootloader that possibly says
"loading", try pressing a few keys. Tab and/or Space generally work
here. Sometimes the bootloader counts down seconds(from 30 or less) to
starting a default OS, this will be what you want to interrupt.

At this point, you should know definatively what bootloader you're
using. Run to another computer and google that bootloader.

Your next step is to convince your bootloader to boot with /dev/sda1 as
root instead of /dev/sda8.

You should hopefully see a list of your possible OS'es to boot(it will
probably only show one, even though we all know you now have two.) With
LILO, I believe you just type on the commandline the name of the
instance you want to load then follow it with root=/dev/sda1

I've only had GRUB since I started using Xen, so I don't recall exactly
what it looks like, but basically you need to tell it where a kernel is
it can boot, and what partition to boot as /(root). Fortunately, GRUB
can look into filesystems and help you with filename completion for th
kernel.

--
Andrew Thompson
http://aktzero.com/

Andrew Thompson wrote:
> At this point, you should know definatively what bootloader you're
> using. Run to another computer and google that bootloader.
>
> Your next step is to convince your bootloader to boot with /dev/sda1 as
> root instead of /dev/sda8.
>
> You should hopefully see a list of your possible OS'es to boot(it will
> probably only show one, even though we all know you now have two.) With
> LILO, I believe you just type on the commandline the name of the
> instance you want to load then follow it with root=/dev/sda1
>
> I've only had GRUB since I started using Xen, so I don't recall exactly
> what it looks like, but basically you need to tell it where a kernel is
> it can boot, and what partition to boot as /(root). Fortunately, GRUB
> can look into filesystems and help you with filename completion for th
> kernel.

Oh, forgot to mention. This is a one-time fix. You should use whatever
method is prescribed by the bootloader on your machine to permanently
convince it to boot to /dev/sda1.

I think GRUB is required for Xen, so go ahead and get it set up and
configured there.

Being able to boot another partition is useful, but not necessary. It
might not be a bad idea to keep a bootable kernel in the /boot of
another partition. That way with a boot disk, you can boot to that
partition if you hose your main install.

Make sure you're moderately happy with the partition scheme you've
configured. I am currently minus my home Xen box because I used parted
to redo my partitions and now GRUB just gives "Error 17" or something
like that... I hope to straighten that out tonight.

--
Andrew Thompson
http://aktzero.com/

Hi Andrew:

Finally I am able to install one Guest OS on my xen machine which is running RedHat 8.0 after I install /dev/sda2 partition first and than install Redhat enterprise version 3 on /dev/sda1 which is my xen machine.

In addition, I find a way to play with Grub to be able to choose which OS to boot after installing multiple OSs in a server. Here is what I found out and hope someone else can
teke it as s reference if it is helpful.

Get to the grub> prompt first. There are two ways to do it,
1) following the grub display menu while you boot the server. There are commands such as
e for editing, c for going to grub command prompt

or
2) after booting the sever, you can type grub command which will lead you to
grub prompt

while in grub>, you can do find /sbin/init
find /vmlinuz
find /boot/vmlinux

which will list all the boot partition info.

e.g. In my case, I will have two entires
(hd0,0) which matches to /dev/sda1 (my RedHat Enterprise version 3)
(hd0,1) which matches to /dev/sda1 (my RedHat 8.0)

to choose which to boot first, you can do the following steps:
e.g. If to choose RedHat 8.0 boot first as an example:


# reboot the machine

You will see RedHat 8.0 Grub will be showing during the boot process.

I will be working on the put RedHat 7.2 on the xen machine as my second Guest OS ...

I hope you will figure out your Error 17 problem soon.

Thank you again, Andrew !

Jeremy


Andrew Thompson <andrewkt@aktzero.com> wrote:
Andrew Thompson wrote:
> At this point, you should know definatively what bootloader you're
> using. Run to another computer and google that bootloader.
>
> Your next step is to convince your bootloader to boot with /dev/sda1 as
> root instead of /dev/sda8.
>
> You should hopefully see a list of your possible OS'es to boot(it will
> probably only show one, even though we all know you now have two.) With
> LILO, I believe you just type on the commandline the name of the
> instance you want to load then follow it with root=/dev/sda1
>
> I've only had GRUB since I started using Xen, so I don't recall exactly
> what it looks like, but basically you need to tell it where a kernel is
> it can boot, and what partition to boot as /(root). Fortunately, GRUB
> can look into filesystems and help you with filename completion for th
> kernel.

Oh, forgot to mention. This is a one-time fix. You should use whatever
method is prescribed by the bootloader on your machine to permanently
convince it to boot to /dev/sda1.

I think GRUB is required for Xen, so go ahead and get it set up and
configured there.

Being able to boot another partition is useful, but not necessary. It
might not be a bad idea to keep a bootable kernel in the /boot of
another partition. That way with a boot disk, you can boot to that
partition if you hose your main install.

Make sure you're moderately happy with the partition scheme you've
configured. I am currently minus my home Xen box because I used parted
to redo my partitions and now GRUB just gives "Error 17" or something
like that... I hope to straighten that out tonight.

--
Andrew Thompson
http://aktzero.com/
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fn:Andrew Thompson
n:Thompson;Andrew
email;internet:andrewkt@aktzero.com
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url:http://aktzero.com/
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